Self-centering feed rolls for a dowel machine or the like



Feb. 5, 1957 c. G. JOA 2,780,253

SELF-CENTERING FEED ROLLS FOR A DOWEL MACHINE OR THE LIKE Filed June 2, 1950 Snventor 60,27 6-. Jan

the respective bulging surfaces 34 and 35 and the rough stock 13 will prevail, but it will be noted (see Fig. 3) that despite the fact that raw stock 12, between my rolls is not an accurately dimensioned square, it is positively centered and the circle 24 indicating the diameter of the dowel 8 is entirely included within the physical dimensions of the rough stock 12.

It will be further noted with respect to feed rolls in Figs. 2, 3 and 6 that the bulging contours of my feed rolls are radially grooved at 36, so that my rolls may engage the stock with a more positive feeding action. Rough stock 12 of such physical characteristics as wood will be slightly compressed by the rolls in a feeding operation sufficiently so that the rough stock will be engaged in grooves 36 for more positive feeding action. The resilient pressure of the rolls against the stock may be adjusted in the machine for this purpose and, obviously, any marking of the rough stock by the rolls is of no consquence, since this stock adjacent the ridges 13 and 16 is completely removed in the dowel making operation.

My new feed rolls are therefore effective to center the rough stock according to the ridge lines 13 and 16. There is no permissible riding of one of these ridges along such a surface as the surface 17 in old style roll 21 and the vertical center line of the rough stock, normal to the axes of the rolls, is brought most closely to the center of the cross section of the rough stock 12.

As is clearly shown in Figs. 2 and 3 the bulging or convex gripping surfaces 34 and 35 are outwardly offset from the frusto-conical surfaces otherwise provided by the outer flange surfaces 32 and 33 respectively. Accordingly, the workpiece 12, as shown in Fig. 3, is gripped only adjacent its diagonally opposed corners to align the center line of the workpiece with the center line of the cutting head of the machine. In this position the work piece is free for self-adjustment relatively without interference by the outer conical flanges 32 and 33 of the rolls.

I claim:

1. A grooved feed roll for stock having a corner ridge to be engaged by the roll, said roll having divergent flanges, the flanges being relatively less sharply divergent at the bottom of the groove and relatively more sharply divergent adjacent the outside of the roll said flanges having inwardly projecting intermediate portions to re- 4 ceive and engage the sides of the corner ridge at points intermediate said less sharply and said more sharply divergent portions of the roll flanges, leaving the apex of the ridge projecting between the less sharply divergent flange portions and out of contact therewith.

2. A grooved feed roll having divergent flanges of frusto-conical form near their outer portions and having inner portions of inwardly convex form, at least part of said convex portions being offset from the frusto-conical portions of the flanges whereby to constitute gripping bulges having line contact with work engaged by the roll.

3. The device of claim 2 wherein the inwardly convex portions of said rolls are provided with laterally extending slits.

4. A pair of cooperating feed rolls for feeding and centering polygonal stock having comer ridges, each of said rolls being provided with two opposed annular inwardly bulging and curvilinearly convex work gripping flanges for substantially line contact with opposite faces of the corner ridges of said stock, the stock being engaged at four points by said flanges and self adjusting between the bulging curvilinearly convex surfaces thereof.

5. A pair of opposed feed rolls for guiding and automatically centering angularly ridged stock and feeding such stock to a dowel machine, each of said rolls having divergent flanges with V-shaped grooves therebetween to receive such stock, the respective flanges each having annular inwardly bulging and substantially continuously curvilinearly convex work-gripping surface for at least a portion of its radial extent whereby the convex portions of the respective flanges concurrently engage the sides of ridged stock in substantial line contact with such sides, the ridges being accommodated in the grooves of said rolls, and the stock being self adjusting between the four flanges of the opposed rolls.

6. The feed rolls of claim 5 in which at least one such roll has its respective flanges provided with outwardly extending slits in its convex work-gripping surfaces.

References Cited in the file of this patent UNITED STATES PATENTS 685,812 Bartholomew Nov. 5, 1901 843,519 Crane Feb. 5, 1907 1,038,514 Anderson Sept. 17, 1912 1,606,313 Martenet Nov. 9, 1 926 

